In western Pennsylvania, where we have a high deer population, gardeners have learned from experience that white-tailed deer will eat some plants and not others. They heavily browse their favorites to the point of killing them but leave others untouched, even plants in the same genus.
In Schenley and Frick Parks you can look straight through the forest if you duck your head below four feet high. In Schenley Park the ground is often bare and most plants in that four-foot zone are gone. But one flower, wingstem (Verbesina alternifolia), is doing just fine in the city parks.
The absence of cover from the ground to 4 – 5 feet is called a browseline (below) and is evidence of an overpopulation of white-tailed deer.
According to this KDKA report, the deer population in Schenley Park is estimated at 80-150, which roughly equates to 100-200 deer per square mile. A healthy population in a balanced forest would be 20-30 deer per square mile, so any plant that survives in the Pittsburgh’s city parks is something that deer don’t eat.
Biennial gaura (Gaura biennis) and honeysuckle vine were both blooming in pink. Interestingly, gaura flowers bloom white and fade to pink, while this non-native honeysuckle starts pink and fades to white and then yellow.
Don’t be fooled by the camera’s perspective. Gaura flowers are very small compared to honeysuckle.
Late August colors came in orange, yellow, purple, gray and green in Frick Park and Moraine State Park.
Above, squash(*) blooms on a fence in Frick.
Yellow daisies without petals are actually tansy (Tanacetum vulgare), native to Eurasia.
The deep purple of New York ironweed (Vernonia noveboracensis) is never true to color in my cellphone photos. Instead it looks redder than expected because the Pixel 5 Photo app apparently overcompensates for the camera’s blue bias. All cameras have problems with purple, described in this vintage article: Not Truly Blue.
This velvety bright orange mushroom in Frick deserved a photo on 25 August. Jim Chapman re-found it the next day and identified it as northern cinnabar polypore (Trametes cinnabarina, a.k.a. Pycnoporus cinnabarinus). By then it was already darker orange than this.
I had never seen the word “synanthrope” until I found it attached to this photo.
House sparrows are synanthropes. So are pigeons.
A synanthrope (syn-anthrope) [from Greek: syn-anthrope: syn=”together with” + anthropos=”man”] is a wild animal or plant that lives near, and benefits from, an association with humans and the somewhat artificial habitats that people create around themselves.
Two local mammals may be recent synanthropes, formerly shunning humans but now benefiting from our habitat.
Squirrels love our birdseed and shelter (attics).
White-tailed deer (Odocoileus virginianus) prefer forest edges next to open areas, a landscape often created by humans. Have deer become synanthropes?
p.s. (*) Merriam-Webster explains that the word was introduced by botanist Theodor von Heldreich at a botanical conference in Paris, 16-24 August 1878, making its first-ever use almost exactly 144 years ago.
Twelve years have passed. According to deer experts “Urban deer can live for 10 years; the deer population, if unchecked, doubles about every two years.” Schenley Park now has as much as 64 times the number of deer we had in 2010. This is truly unsustainable, even for the deer themselves.
Schenley’s deer have completely consumed all the good food plants and are starting to nibble the poisonous ones. The browse line is painfully obvious. In the process deer have eradicated their favorite plants from Schenley Park.
Orange jewelweed and yellow jewelweed provide nectar for hummingbirds and bumblebees and are a favored food of deer.
Both jewelweeds were prolific in Schenley Park as recently as four years ago.
But this year all the accessible plants have been eaten down to bare stems. The only ones that flower are those in spots unreachable by deer — on extremely steep slopes or hidden among thick cattails in Panther Hollow Lake.
Jewelweeds are annuals that must re-seed every year but no seeds are produced in this deer-browsed landscape. Impatiens will disappear from Schenley Park when the seed bank is exhausted.
False Solomon’s seal used to grow throughout Schenley Park and it carpeted the ground in an area near the Bridle Trail. All of it has been eaten to the ground since 2014. Here’s what it looked like eight years ago.
White wood asters used to bloom in Schenley’s woods. Not anymore. Here’s what they looked like in 2013.
Eradicated plants are indirect evidence of too many deer in Schenley Park. Direct evidence is their visibility every day.
A sustainably-sized deer herd would hide in the underbrush while sleeping during the day, but the browse line in Schenley is so severe there is no cover for them. The large herd has coped by becoming accustomed to people and leashed dogs.
I stood near this group of three deer on Sunday 21 August using my snapshot camera zoomed to 90mm (approximately 2x). This 8-point buck did not care that I was there.
Yews are popular landscaping shrubs but they don’t last long in the face of deer overpopulation.
All yew species are toxic to some degree, but our native Taxus canadensis is less toxic than others and was used medicinally. Deer don’t read the warning labels. They love yew.
Every night they creep up behind Carnegie Museum and browse the yews along the driveway to the parking garage. They nip off the small branches and eat all the leaves. The shrubs struggle to grow new leaves for photosynthesis before the deer return.
Deer have killed the yews closest to the sidewalk (dead twigs), overbrowsed the middle shrubs (green knobs), and cannot yet reach the tallest branches. But they are eating their way there.
Don’t assume their love stops with yew. There are more delectables in Schenley Park that they adore. Soon we’ll explore more.
Sometime this summer the Department of Public Works placed a large sandstone rock at the base of the stairs behind the Schenley Park Visitors’ Center. The prominent fossil facing the stairs tells a story about life in Pittsburgh 300 to 330 million years ago.
The sand became sandstone and in the early 21st century the rock separated from its fellows thereby exposing the fossil. This rock many have fallen at the Bridle Trail rockslide.
I have never seen Lepidodendron’s closest living relative, Lycopodium, in Schenley Park …
… but I’ll look for it now that I’ve seen its fossil ancestor.
Thank you to Public Works for placing this fossil rock on display in Schenley Park.
p.s. If this Lepidodendron had fallen in a swamp instead of on a sandy beach, it would have become coal. Read about similar fossils at Ferncliff Peninsula in Ohiopyle State Park in this vintage article: Fossils at Ferncliff
(photos by Kate St. John, illustrations from Wikimedia Commons; click on the captions to see the originals)